Classifications

• • G—PHYSICS
  • G11—INFORMATION STORAGE
  • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
  • G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
  • G11B7/08—Disposition or mounting of heads or light sources relatively to record carriers
  • G11B7/09—Disposition or mounting of heads or light sources relatively to record carriers with provision for moving the light beam or focus plane for the purpose of maintaining alignment of the light beam relative to the record carrier during transducing operation, e.g. to compensate for surface irregularities of the latter or for track following
• • G—PHYSICS
  • G11—INFORMATION STORAGE
  • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
  • G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
  • G11B7/08—Disposition or mounting of heads or light sources relatively to record carriers
  • G11B7/09—Disposition or mounting of heads or light sources relatively to record carriers with provision for moving the light beam or focus plane for the purpose of maintaining alignment of the light beam relative to the record carrier during transducing operation, e.g. to compensate for surface irregularities of the latter or for track following
  • G11B7/0938—Disposition or mounting of heads or light sources relatively to record carriers with provision for moving the light beam or focus plane for the purpose of maintaining alignment of the light beam relative to the record carrier during transducing operation, e.g. to compensate for surface irregularities of the latter or for track following servo format, e.g. guide tracks, pilot signals
• • G—PHYSICS
  • G11—INFORMATION STORAGE
  • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
  • G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
  • G11B7/08—Disposition or mounting of heads or light sources relatively to record carriers
  • G11B7/09—Disposition or mounting of heads or light sources relatively to record carriers with provision for moving the light beam or focus plane for the purpose of maintaining alignment of the light beam relative to the record carrier during transducing operation, e.g. to compensate for surface irregularities of the latter or for track following
  • G11B7/0901—Disposition or mounting of heads or light sources relatively to record carriers with provision for moving the light beam or focus plane for the purpose of maintaining alignment of the light beam relative to the record carrier during transducing operation, e.g. to compensate for surface irregularities of the latter or for track following for track following only
  • G11B7/0904—Dithered tracking systems
• • G—PHYSICS
  • G11—INFORMATION STORAGE
  • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
  • G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
  • G11B7/24—Record carriers characterised by shape, structure or physical properties, or by the selection of the material
  • G11B7/2407—Tracks or pits; Shape, structure or physical properties thereof
  • G11B7/24073—Tracks
  • G11B7/24082—Meandering

Definitions

• the invention relates to an optical scanning device which scans a recording medium using the three-beam method, the data tracks of which are wobbled in the radial direction around their central position.
• EP-A 0 256 984 discloses a p-shaped recording medium, the data tracks of which are swept around a center frequency.
• the data tracks therefore have a sinusoidal shape.
• the advantage of this special form of the data tracks is that they can carry additional information, for example position information.
• One disadvantage, however, is that tracking is made more difficult due to the wobbled data track. High demands are therefore placed on the tracking control loop. It is therefore an object of the invention to achieve precise tracking by means of a simple tracking control loop in spite of wobbled data tracks on an optical scanning device according to the preamble of the main claim.
• the invention solves this problem in that the distance between the 1st order and 1st order diffraction beam, which generate the tracking error signal, on the recording medium is an integral multiple of the wavelength belonging to the center frequency, with which the data tracks wobble around their center position become.
• Figure 2 shows the position of the light rays on the wobbled
• FIG. 2 shows a wobbled data track S on a recording medium CD.
• the data is scanned with the main light beam L1.
• the distance between the + 1st and - 1st order diffraction beams that generate the tracking error signal is n * T, where n is an integer and T is the wavelength belonging to the center frequency.
• the two diffraction beams are labeled L2 and L3.
• the wobbled data track cannot modulate the track error signal generated from the diffraction beams L2 and L3. Because there is therefore no disturbance in the track control loop caused by the wobble of the data track, the track control loop can be opened just as easily as for a recording medium without a wobbled track be built. There are no higher demands on the tracking control loop.

Landscapes

• Optical Recording Or Reproduction (AREA)
• Optical Communication System (AREA)
• Vehicle Body Suspensions (AREA)
• Investigating Or Analysing Materials By Optical Means (AREA)
• Moving Of The Head For Recording And Reproducing By Optical Means (AREA)
• Holo Graphy (AREA)

Priority Applications (4)

Applications Claiming Priority (2)

Publications (1)

Family

ID=6385049

Family Applications (1)

Country Status (14)

Cited By (1)

Families Citing this family (8)

Citations (2)

Family Cites Families (1)

• 1989
  • 1989-07-14 DE DE3923330A patent/DE3923330A1/de not_active Withdrawn
• 1990
  • 1990-06-29 DE DE59007160T patent/DE59007160D1/de not_active Expired - Lifetime
  • 1990-06-29 HU HU9219A patent/HUT60560A/hu unknown
  • 1990-06-29 EP EP90910647A patent/EP0485404B1/de not_active Expired - Lifetime
  • 1990-06-29 AT AT90910647T patent/ATE111627T1/de not_active IP Right Cessation
  • 1990-06-29 AU AU60409/90A patent/AU6040990A/en not_active Abandoned
  • 1990-06-29 WO PCT/EP1990/001039 patent/WO1991001551A1/de active IP Right Grant
  • 1990-06-29 JP JP2510275A patent/JP2877952B2/ja not_active Expired - Lifetime
  • 1990-06-29 KR KR1019920700076A patent/KR920704280A/ko not_active Application Discontinuation
  • 1990-06-29 ES ES90910647T patent/ES2061051T3/es not_active Expired - Lifetime
  • 1990-07-13 MY MYPI90001183A patent/MY105973A/en unknown
  • 1990-07-13 DD DD90342780A patent/DD296773A5/de not_active IP Right Cessation
  • 1990-07-14 CN CN90104614A patent/CN1019428B/zh not_active Expired
• 1992
  • 1992-01-16 US US07/880,940 patent/US5247507A/en not_active Expired - Lifetime
• 1995
  • 1995-05-04 HK HK68995A patent/HK68995A/xx not_active IP Right Cessation

Patent Citations (2)

Non-Patent Citations (3)

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